Telegraph code converter



Jan. 4, 1949. l G. L. BUSH v 2,458,144

TELEGRAPH CODE CONVERTER Filed April 19, 1946 is M2 (5T) Gs' GM' 40u Em' PULSE TO P-i FIG EXP/- INVENTOR. G. I .BUSH

/iM/.MMJ

ATTORNEY.

Patented Jan. 4, 1949 TELEGRAPH CODE CONVERTER George L. Bush, Flushing, N. Y., assigner to The Teleregister Corporation, New York, N. Y., a corporation of Delaware Application April 19, 1946, Serial No. 663,367

7 Claims. 1

This invention relates to a telegraph code converter, and more particularly to improved means for changing permutation ycode telegraph signals having a given number of code units to permutation code signals having a diilerent number of code units.

In printing telegraph transmitting and repeating systems, the permutation code signals are initially perforated or are received on a tape reperforator whereby they may be stored in the tape pending transmission or retransmission over an outgoing circuit. The signals originally may comprise, for example, -unit code signals, and if it is desired to transmit or relay them over a circuit in a different code, for example, to a -unit code telegraph printer, it is necessary to interpolate shift and unshift code groups at the proper times to condition the printer to record in the proper case, depending upon whether an upper case or a lower case character is to be recorded.

One of the objects of the present invention is a telegraph code converter which may be employed with conventional transmitting equipment in such manner that the equipment does not have to be modied or changed in order to effect conversion from one code to another.

Another object is a code converter adapted to operate with a tape transmitter, in which local distributor rings for stepping the tape transmitter are not required.

Another object is a code converter in which the likelihood of clipped pulses is obviated, and in which closer timing of the received and retransmitted pulses may be effect/ed.

An additional object is a code converter which is capable of operating at speeds that are limited only by the time required for stepping the tape transmitter with which it is employed.

Other objects and advantages of the invention will be apparent from the following description, taken in connection with the accompanying drawings in which:

Fig. 1 is a circuit diagram of a preferred form of code converter inv accordance with the instant invention;

Fig. 2 illustrates a modied form of circuit control which may be employed in the code converter; and

Fig. 3 is a timing chart in regard to the various elements of the converter shown in Fig. l.

Referring now to Fig. 1 of the drawings, there is shown diagrammatically a 6-unit code tape 'transmitter TT, and a rotary retransmitting distributor DR for transmitting in -unit code over a line L the signals stored in the tape as it is passed through the tape transmitter TT, the 5- unit code signals being suitable for operating start-stop telegraph apparatus, for example, a 5-unit code printer PR. The code converter is operatively interposed between the 6-unit code tape transmitter and the 5-unit code retransmitting distributor, and as indicated at I0 and l2 the converter unit may embody slip connections so that it can readily be connected to conventional transmitter and distributor apparatus. The converter unit may be made portable and can be connected in a few minutes to existing circuits wherever the need for code conversion may .arise and, conversely, may easily be disconnected from such circuits whenever it is desired. The messages to be transmitted or relayed are stored by means of transverse rows of perforations punched in a tape by a 6-unit code tape perforator TP of conventional construction it being understood that the perforated tape t which issues from the perforator is passed over the tape feeler pins SH and l to 5 of the tape transmitter TT in usual manner.

When brush B of rotary distributor DR is on the stop segment Sp of the distributor, the marking signal holds stop relay SP operated in preparation for the start of the next character from the tape transmitter TT, the circuit comprising conductor I4 and winding of relay SP to negative marking battery I6. The brush B of distributor DR is under control oi a start magnet SM, the circuit of which magnet passes through a tight loop control tape switch TTS so that when the switch contacts are closed, the magnet SM is energized, thereby releasing the distributor brush for rotation. The tight tape switch is controlled in conventional manner, that is, by the loop of tape t which issues from a G-unit code tape perforator TP whereby when there is a message waiting in the perforated tape, the distributor DR will operate, and when the loop of tape between the perforator TP and the tape transmitter TT becomes less than a predetermined amount, the tape opens the contacts of the switch TTS and stops transmission from distributor DR, the distributor in turn controlling the operation of the tape transmitter TT.

As the brush B leaves the stop segment Sp, the energizing circuit of relay SP is opened and the relay releases. The release of relay SP, through its grounded armature I8 and left hand break contact, causes operation of a slow acting relay TSC. The operation of TSC partially prepares an operating circuit for the transmitter 3 tape stepping magnet TS, the circuit extending from negative battery through the magnet TS, lower armature 2i? and make contact of relay TSC,

lower armature 22 and break contact of the FIG- ments i to 5 of the segmented'ring of- DR, and.

thus the marking and spacing pulses of the character previously set up on the contacts of the tape transmitter TT are applied, through the armatures 2 to 28 and upper break contacts of. the FIG-LET relay, to the segments i to 5, and will be transmitted overy the line L through the brush Band the solid ring of the distributor. After the brush thus completes its rstrevolution, the waiting character onv thel tape transmitter has been transmitted as a 5-unitl code signal over the line. the stop segment the SP relay again operates, and at its armature iand inner make contact completes the circuit to the tape stepping magnet TS, th-us advancing the tape one step in thetape transmitter.

At the time theSP relay operates it opens the energizing circuit of relay TSC, but since the latter is a slow acting relay this provides a suii.- cient length of time to completely operate the tapestepping magnet TS before it releases, eX- cept that the tape stepping magnet is released before the brush B of distributor DR leaves the stop segment Sp. Thereason for deenergizing the stepping magnet i TS before the brushv B advances to the next segment of the distributor ring is to ensure that the feeler pins SH and IA to 5 of the tape transmitter will have engaged the next series of perforations in the tape in suicient time to determine whether the character being set up represents a change in case from letters to figures or vice versa. When brush` B reaches the start segment St, the relay ST operates from positive battery 30 applied to conductor 3l and thence through the relay and distributor rings to line L which: is grounded at the distant end. The oper-ation of relay ST completes a circuit from the shift contact of the tape transmitter TT to a polar relay P of the stay-put type andY if there. is a change in the polarity of the current applied to the polar relay, it will operate. The operating circuit for relay P may be traced from. battery on either the marking ring M or spacingv bus S.V of tape transmitter TR, through the shift contact SH, armature'36 and break contact ofy slow acting relay PC, conductor 38, inner. armature 39 and make contact of relay ST, conductor til and winding l of polar relay P to ground the operated position of the relay and its armatures depending upon the polarity of theoperating current as determined by the position of. the shift contact SH.. Winding 2r of the relay is a polarizing winding. Armatures ft2 and 43 of the polar relay P in operating operate relay FIG-LET whichV is acase-shiftV control relay.. It will-be noted that the circuit of thel operate winding I of the FIG-LET relay includes a grounded condenser 4i? with af resistance 45. in. series with the winding anclthe condenser. The purpose of this'isto provide a circuit which when it is once When the brush arrives atV operated will deenergize without opening the circuit. The operation of the FIG-LET relay is arranged so that when the P relay operates, the operating winding i vof the FIG-LET relay will be energized only during the charging or discharging time of the condenser, after which the holding winding 2 of the relay controls the operation thereof; thus the relay may be released, under control of relay TSC; at the end of the transmission of a shift character even though the polar relay P does not release. The arrangement insures that the FIG-LET will not reoperate inadvertently due to the stay-put characteristic ofv the-polar relay P. The value of the condensenmay vary, depending upon the constants of the particular circuit employed; in the circuit illustrated if the locking armature 138 of the FIG-LETrelay is of the preliminary make type so`v that it closes the locking circuit of the relay before the other armatures '22 and 2li to 28 begin to move, the condenser may have a value of the order of 20 mfds. or lower. Ii a preliminary make armature is not employed then the value of the condenser must be appreciably greater in view of theload imposed by the armatures, The resistance which operates as spark protection for the contacts of the P relay may have a value ofthe order of 1500 ohms.

Assuming that the case is to be changed, relay P will have operated, thereby causing operation of the FIG-LET relay which disconnects, at its armatures 24 to 25 and upper break contacts, the tape transmitter from the distributor and marks the segments l to 5 of the distributor with the letters, or gurescode depending upon whether a letters or gures code was in progress. The

FIG-LET relay in operating is locked through its No. 2 winding and its lower inner make contact and armature t8-, tothe inner armaturefandl break contact of the TSC relay. When the distributor DR comes to the stop segment Sp, the SP relay operates over conductor i4, partially preparing the circuit to the tape stepping magnet TS, butv the latter does not step at this time because its circuit is open at the lower armature 22 and break contact of the operated FIG-LETv relay. The reason for this is` that the character which' has been set upv in the tape transmitter should be.A retained until the case signal has been transmit-ted,` and thus the tape should not be stepped. at this time. The TSC relay releases when the distributor brush contacts the Sp segment onf the distributor, andv in releasing its armature 49 releases the FIG-LET relay sov that when the brush progresses, tof segment iv off the ring, the tape transmitter aga-in is connected with the distributor, andduring the travel of the distributor brush over segments l to 5', the rst character in the tape transmitter which follows the case signal wil be transmitted.

Thereafter,v the, characters successively set up on the transmittercontacts will be applied to the transmitting segments of the-distributor during successive revolutions of the brush B until there agains occurs a changein the case condition of a character, whereupon a case shift signal will again be introduced; The previous case shift sig` nal was assumed to be from letters to igures, and consequently the next case shift signalV will be from gures to letters. When this signal is set up on the shift contacts SH of thetape transmitter, they will be' in contact with the negative or marking busof the tape transmitter.V This will; cause, when distributor brush B is in contact. with the start segment St, the operation of theV polar relay P to remove positive spacing battery 30 from its upper armature 52, so that the shift signal now applied to the distributor segments I to 5 will be all marking in character, negative battery representing marking. There will thus be transmitted a letters shift signal to the line L, while the character set up in the tape transmitter TR is retained until the succeeding revolution of the distributor brush B, in the manner aforesaid.

The relay PC, and its control circuit through the outer armature 54 and make contact of the start relay ST is for the purpose of opening, at armature 36 of relay PC, the circuit to winding I of the polar relay P so that the load of the P relay will not appeal on the marking resistance 60 in the tape transmitter circuit when the brush B begins to pass over distributor segment No. l. In other words, this insures that the winding of the P relay will be disconnected from the battery circuit through the resistance E before the brush B contacts any of the transmitting segments l to 5, and thus prevent the winding of the P relay from acting as a shunt which would cut down the line current transmitted.

The circuit from the shift contacts SH of the transmitter may be simplified if the battery supply busses of the tape transmitter are divided so that separate marking and spacing busses are employed for the shift contacts. In such an arrangement, and as illustrated in Fig. 2 of the drawings, the circuit from the marking bus M2 may be connected directly to an armature 39 on the start relay ST. This circuit also eliminates the necessity for using a relay such as the PC relay shown in Fig. l.. The only diiference insofar as the timing characteristics of the circuit are concerned is that with the arrangement of Fig. 2, the polar relay P will be energized for a slightly longer period than with the arrangement of Fig. l, but the winding of the polar relay will not be loading the resistance 60 in the marking battery supply since separate shift busses S2 and M2 are employed- Fig. 3 is a timing chart of the relays in the circuit of Iig 1. Referring to the chart, it will be apparent that at the time the distributor brush B engages the stop segment Sp, relay TSC previously has been operated. Shortly after the brush engages segment Sp, the relay SP operates. SP remains operated until the brush B leaves the Sp distributor segment, the release time of the relay being represented by the slant line from the beginning of segment St to the end of the line. Relay TSC is released by the contacts of relay SP, the time of release being indicated on the chart. The release time of TSC is indicated by the slant line from the beginning of line SP to the end of line TSC. During the release time of relay TSC a pulse is generated for operating the tape step magnet TS, the length of this pulse being shown by line TS on the chart. The periods of contact of the tape transmitter tongues SH and l to 5 with the marking or spacing busses S and M is indicated at TT; the rst period terminates at the time the brush B has almost reached the center of the segment Sp. The first interval, when the transmitter tongues are out of contact with the busses is shown at s in the chart, and following this interval is shown the length of time that the transmitter tongues are in contact with the spacing bus S, at which time the tape feeler pins are withdrawn from the tape. Following the next interval s', the tape transmitter tongues selectively engage the marking and spacing buses depending upon 6 the particular signal to be transmitted, and as indicated the tongues remain in contact with thebuses during the remainder of the revolution of the brush.

Relay ST begins to operate at the time the distributor brush engages the start segment St, the operate time being indicated on the chart, and the relay ST releases at the time the brush reaches approximately the middle oi segment i. The operation oi relay ST causes operation of relay PC, the operate time of PC being indicated on the chart, and PC restores when the distributor brush has passed the middle of segment 2.

The pulse to relay P is quite short, as established by relay SP and opened by relay PC. The operate time of relay P is shown directly below the line showing the length of the pulse, and the FIG-LET relay, which is operated upon operation of relay P, is shown below the line representing relay P.

Referring again to Fig. 1, the reversing action of the two inner upper armatures 42, 43 and contacts of relay P, which control the condenser circuit that operates the FIG-LET relay, is to v insure that both the charging current and the discharging current of the condenser circuit will pass through the operate winding l of the relay in the same direction, and in a direction. to aid the locking winding of this relay. In other words, if when the condenser is charging and current is flowing in a direction through the operate winding such that it aids the locking winding of the relay, then when the circuit was discharging dur ing the next cycle of operations, the current passing through the operate winding would be in a direction tending to neutralize the effect of the current passing through the locking winding, which would thereby prevent the relay from locking up.

Various modifications of the apparatus and circuit arrangement of the specic embodiment shown, and Various equivalents or substitutes for the devices illustrated, will readily occur to those versed in the art without departing from the spirit or scope of the present invention. The disclosure, therefore, is for the purpose of illustrating the principles of the invention, which is not to be regarded as limited except as indicated by the scope of the appended claims.

I claim:

1. In a printing telegraph system having an automatic transmitter and a distributor with a segmented ring having a start segment, a stop segment and intervening code segments or transmitting start-stop permutation code signals to a receiver, and in which the code representation controlling the transmitter differs in certain characters from the normal operating code of the receiver; means for converting the code representations of certain characters involving a change in case, comprising a case-shift relay, circuit means controlled by said relay for marking said code segments of said transmitting ring to interpolate case-shift signals whenever the next character to be transmitted involves a change in case, means including another relay controlled jointly by said automatic transmitter and the start segment of said transmitting ring for operating said case-shift relay, and means controlled jointly by one of said relays and said stop segment of the transmitting ring for stopping said transmitter during transmission by said distributor of a case-shift signal.

2; In a printing telegraph system having an automatic transmitter and a distributor with a segmented ring having' a start segment, a stop segment andv intervening code segments for transmitting start-stop permutation code signals to a receiver, and in which the code representation controlling the transmitter differs in certain characters from the normal operating code of the receiver; means' for converting the code representations' of certain characters involving a change in case', comprising a ease-shift relay, circuit means controlled by said relay for marking said code segments of said transmitting ring to interpolate case-shift signals whenever the next character to be transmitted involves a change in case, a second relay controlled by the start segment of said transmitting' ring, means including a third relay controlled jointly by said automatic transmitter and said second relay for operating said case-shift relay, and means controlled jointly by one of said relays and said stop segment of the transmitting ring for stopping said transmitter during transmission by said distributor of a case-shift signal.

3. In a printing telegraph system having an automatic transmitter and a start-stop distributor with a segmented ring having a start segment, a stop segment and intervening code segments for transmitting permutation code signals to a receiver, and in which the code representation controlling the transmitter differs in certain characters from the normal operating code of the receiver; means for converting the code representations of certain characters involving a change in case, comprising a case-shift relay, circuit means controlled by said relay for marking said code segments of said transmitting ring to interpolate case-'shift signals Whenever the next character to be transmitted involves a change in case, means including another relay controlled jointly by said automatic transmitter and the start segment of said transmitting ring for operating said case-shit relay, and means controlledA jointly by said case-'shift relay and the stopseg-,r-A

ment of said transmitting ring for stopping said transmitter during transmission b-y said distributor of a case-shift signal.

ai. In a printing telegraph system having an automatic transmitter and a start-stop distributor With a segmented ring having a start segment, a stop segment and intervening 'code segments for transmitting permutation code signals to a receiver, and in which the code representation controlling the transmitter diifer's in certain characters from the normal operating code of the receiver; means for converting the code representations of certain characters involving a change incase, comprising a case-shift control relay, vcircuit connections including a group of armatures and contacts on said relay for marking segments of said 'transmitting ring to interpolate case-shift signals Whenever the next character to be transmitted involves a change in case, 'a second relay controlled by the start segment of said transmitting ring, means including aithirdrelay controlled jointly by said automatic transmitter and said second relay for operating said case-shift relay, means including an armature and contacts on said third relay for changing the 'circuit connections through 'cert'ain of the armatures and cont, cts of the case-shift relay'to determine whether a letters shift or a figures shift signal is transmitted, and means controlled by one oi said relays for .stopping said transmitter during transmission by said distributor of a case-shift signal.

5. In a printing telegraph. 'system having a tape transmitter and an associated start-'stop distributorwith' 'a segmented ring for tranemitting ing a group of armatures and contactsv on said relay for marking segments of said transmitting ring to interpolate case-shift signals whenever the next character to be transmitted involves a change in case, a second relay controlled by the start segment of said transmitting ring, a second and' third relay controlled by said second relay, said third relays controlling a case-shift circuit fromwsaid transmitter contacts, a polar relay controlled jointly by said transmitter contacts and the case-shift circuit through said second and third relays for operating said case-shift relay, and means including one of said relays for controlling the tape-stepping magnet of the tape transmitter.

6. In a printing telegraph system having a tape transmitter and a start-stop distributor with a segmented ring for transmitting permutation code signals to a receiver, and in which the code representation controlling the transmitter differs in certain characters from the normal operating code of the receiver; means for converting the code representations oi certain characters involving a change in case, comprising a case-shift relay, circuit connections including a group of armatures and contacts on said relay for marking segments of said transmitting ring to interpolate case-shift signals Whenever the next character to be transmitted involves a change in case, a second relay controlled by the start segment of said transmitting ring, means including a polar relay controlled jointly by contacts on said tape transmitter and said second relay for operating said case-shift relay, means including an armature and contacts on said polar relay for changing the circuit connections through certain of the armatures and contacts of the case-shift relay to determine Whether a letters shift or a iigures shift signal is transmitted, a fourth relay controlled by the stop segment of said transmit-v ting ring, and circuit means jointly controlled by said fourth relay and one of said other relays for controlling the tape-stepping magnet of the tape transmitter.

7. In a printing telegraph system having a tape transmitter and a start-stop distributor with a segmented ring for transmitting permutation code signals to a receiver, and in which the code representation controlling the transmitter differs in certain characters from the normal operating code of the receiver; means for converting the code representations of certain characters involving a change in case, comprising a case-shift relay, circuit connections including a group of armatures and contacts on said relay for marking segments of said transmitting ring to interpolate case-shift signals whenever the next character to be transmitted involves a change in case, a second relay controlled by the start segment of said transmitting ring, means including a polar relay controlled jointly by contacts on said tape transmitter and said second relay for operating said case-shift relay, a fourth relay controlled by the .stop segment of said transmitting ring, a slow-operating relay controlled by said fourth relay, and circuit means jointly controlled by said slow-operating relay, vsaid fourth relay and 9 said case-shift relay for actuating the tapestepping magnet of the tape transmitter, said slow-operating relay providing a sulcient length of time to insure complete operation of the tapestepping magnet by its actuating circuit.

GEORGE L. BUSH.

10 REFERENCES CITED The following references are of record in the me of this patent:

UNITED STATES PATENTS Number Name Date 2,152,772 Potts Apr. 4, 1939 2,109,989 Dirkes Mar. 1, 1938 

